U.S. patent number 5,514,766 [Application Number 08/405,316] was granted by the patent office on 1996-05-07 for di-, tri- and tetrafunctional methyl isobutyl and methyl amyl ketoxime-based silanes.
This patent grant is currently assigned to AlliedSignal Inc.. Invention is credited to Edward T. Asirvatham, Dale R. Flackett, Jeffrey A. Knepper, Chempolil T. Mathew.
United States Patent |
5,514,766 |
Mathew , et al. |
May 7, 1996 |
**Please see images for:
( Certificate of Correction ) ** |
Di-, tri- and tetrafunctional methyl isobutyl and methyl amyl
ketoxime-based silanes
Abstract
The invention relates to the following novel silanes: methyl
vinyl bis-(methyl isobutyl ketoximino) silane; methyl vinyl
bis-(methyl amyl ketoximino) silane; methyl tris-(methyl isobutyl
ketoximino) silane; vinyl tris-(methyl isobutyl ketoximino) silane;
methyl tris-(methyl amyl ketoximino) silane; vinyl tris-(methyl
amyl ketoximino) silane; tetrakis-(methyl isobutyl ketoximino)
silane; tetrakis-(methyl amyl ketoximino) silane; methoxy
tris-(methyl isobutyl ketoximino) silane; ethyl tris-(methyl
isobutyl ketoximino) silane; ethoxy tris-(methyl isobutyl
ketoximino) silane; methoxy tris-(methyl amyl ketoximino) silane;
ethyl tris-(methyl amyl ketoximino) silane; ethoxy tris-(methyl
amyl ketoximino) silane; and mixtures thereof.
Inventors: |
Mathew; Chempolil T. (Randolph,
NJ), Asirvatham; Edward T. (Chatham, NJ), Knepper;
Jeffrey A. (Somerville, NJ), Flackett; Dale R.
(Somerset, NJ) |
Assignee: |
AlliedSignal Inc. (Morristown,
NJ)
|
Family
ID: |
22569124 |
Appl.
No.: |
08/405,316 |
Filed: |
March 16, 1995 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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158660 |
Nov 29, 1993 |
5405930 |
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Current U.S.
Class: |
528/34;
556/422 |
Current CPC
Class: |
C07F
7/0892 (20130101); C08L 83/04 (20130101); C07F
7/04 (20130101); C08L 83/04 (20130101); C08L
2666/44 (20130101); C08G 77/16 (20130101); C08G
77/18 (20130101) |
Current International
Class: |
C08L
83/04 (20060101); C08L 83/00 (20060101); C07F
7/00 (20060101); C07F 7/08 (20060101); C08G
077/04 (); C08F 007/04 () |
Field of
Search: |
;528/34 ;556/422 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0369359A3 |
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May 1990 |
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EP |
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4141552 |
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Jun 1992 |
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DE |
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Other References
Goel et al. Untersuchengen ueber die diamagnetische
Suszeptibilitaet einiger Organ(imino-oxy)silane; Monatshefte fur
Chemie, vol. 107, No. 2, 1976, pp. 531-535. .
Singh et al., Synthesis and Characterisation of some
Organo(imino-oxy)silane; Journal of the Chemical Society, Dalton,
No. 17, 1972, pp. 1911-1913. .
Singh et al. Organometallic Oximes and Allied Derivaties,
Preparation and Characterization of some New Tris-(iminoxy)
Organosilanes, Chemical Abstracts; vol. 84, No. 7 (Feb. 16, 1976)
Abstract No. 44260y. .
Rupani et al.; Synthesis and Characterization of Some New
Organo(Iminoxy)silanes; Chemical Abstracts, vol. 92, No. 17 (Apr.
28, 1980) Abstract No. 146832u..
|
Primary Examiner: Marquis; Melvyn I.
Assistant Examiner: Dean; Karen A.
Attorney, Agent or Firm: Gianneschi; Lois A.
Parent Case Text
This application is a division of application Ser. No. 08/158,660,
filed Nov. 29, 1993 now U.S. Pat. No. 5,405,930.
Claims
What is claimed is:
1. A silicone rubber composition comprising a hydroxy-endblocked
siloxane polymer and a ketoxime silane of the formula:
where R' is any saturated straight chain or branched alkyl radical
of 3 to 7 carbon atoms; R" is methyl; and R1 is any alkoxy radical
of 1 to 8 carbon atoms, and a is a positive integer ranging in
value from 2 to 4.
2. The silicone rubber composition of claim 1 wherein R' is
selected from propyl, isopropyl, butyl, isobutyl and amyl.
3. A method of making a one-component room-temperature-curing
system comprising reacting in the substantial absence of moisture a
hydroxy-endblocked siloxane polymer with the silane of claim 1.
4. A method of making a one-component room-temperature-curing
system comprising reacting in the substantial absence of moisture a
hydroxy-endblocked siloxane polymer with the silane of claim 2.
Description
BACKGROUND OF THE INVENTION
A variety of useful silicone compositions cure at room temperature
to elastomeric materials which possess a broad spectrum of physical
and chemical properties. These compositions are particularly
desirable because they surface cure in thirty minutes or less after
exposure to the atmosphere but remain substantially soft for years.
They also adhere tenaciously to a wide variety of materials such as
glass, porcelain, wood, metal and organic plastics. Because of
this, they are adaptable for practically any type of sealant
application including building and automotive equipment
applications. The following patents discuss some of these compounds
in more detail.
U.S. Pat. No. 3,189,576 to Sweet describes oxime silanes useful in
the manufacture of room temperature curing compositions.
Specifically, Sweet teaches trifunctional and tetrafunctional
ketoximino silanes as crosslinkers and their use in the manufacture
of room temperature curing silicone elastomeric compositions by
mixing them with hydroxyl endblocked polydiorganosiloxanes. These
compositions can also contain fillers and curing catalysts.
U.S. Pat. No. 4,503,210 to Von Au discloses mixtures of tri- and
tetrafunctional ketoximino silanes and focuses specifically on the
usefulness of tetrafunctional ketoximino silanes in sealant
formulations.
The problem with known tetrafunctional oximino silanes (i.e., e.g.,
those based on methyl ethyl ketoxime (MEKO) and acetone oxime) is
that they are solids at room temperature. Since such compounds are
very sensitive to moisture they decompose easily to semisolids
which are difficult to handle. Thus, these materials have a poor
shelf life and require special care in their packaging and
transporting.
The known tetrafunctional and trifunctional oximino silanes (i.e.,
e.g., those based on MEKO and acetone oxime) have other drawbacks.
Traditionally, when these materials have been combined with
silicone polymers the resulting product has been opaque. This has
substantially limited the applications in which these materials can
be used.
As the applications in which room temperature curing compositions
can be utilized continue to increase, the specific kinds of
properties required of these compositions continue to change. The
art is continually looking for room temperature curing compositions
having new desirable properties without the old undesirable
properties like opacity and physical state limitations (solids). We
have surprisingly discovered that the silanes of the invention
satisfy this need in the art.
DESCRIPTION OF THE INVENTION
The invention relates to silanes of the formula:
where R' is any saturated straight chain or branched alkyl radical
of 3 to 7 carbon atoms such as propyl, isopropyl, butyl, isobutyl
and amyl; R" is methyl; and R1 is any saturated, straight chain
alkyl or alkoxy radical of 1 to 8 carbon atoms such as methyl,
ethyl and propyl or an alkenyl radical of 1 to 5 carbon atoms such
as methyl, vinyl and allyl and a is a positive integer ranging in
value from 2 to 4. More specifically, the invention relates to the
following silanes: methyl vinyl bis-(methyl isobutyl ketoximino)
silane; methyl vinyl bis-(methyl amyl ketoximino) silane; methyl
tris-(methyl isobutyl ketoximino) silane; vinyl tris-(methyl
isobutyl ketoximino) silane; methyl tris-(methyl amyl ketoximino)
silane; vinyl tris-(methyl amyl ketoximino) silane;
tetrakis-(methyl isobutyl ketoximino) silane; tetrakis-(methyl amyl
ketoximino) silane; methoxy tris-(methyl isobutyl ketoximino)
silane; ethyl tris-(methyl isobutyl ketoximino) silane; ethoxy
tris-(methyl isobutyl ketoximino) silane; methoxy tris-(methyl amyl
ketoximino) silane; ethyl tris-(methyl amyl ketoximino) silane;
ethoxy tris-(methyl amyl ketoximino) silane; and mixtures
thereof.
In a preferred embodiment, the ketoxime silanes are selected from
methoxy tris-(methyl isobutyl ketoximino) silane; ethoxy
tris-(methyl isobutyl ketoximino) silane; methoxy tris-(methyl amyl
ketoximino) silane; and ethoxy tris-(methyl amyl ketoximino)
silane. In another preferred embodiment, the ketoxime silane is a
mixture of tetrakis-(methyl isobutyl ketoximino) silane and at
least one of methoxy tris-(methyl isobutyl ketoximino) silane
ethoxy tris-(methyl isobutyl ketoximino) silane; methoxy
tris-(methyl amyl ketoximino) silane; ethoxy tris-(methyl amyl
ketoximino) silane; methyl tris-(methyl isobutyl ketoximino) silane
and methyl tris-(methyl amyl ketoximino) silane. A one-component
room-temperature-curing system may be prepared by reacting a silane
of the above formula with a hydroxy-endblocked silane polymer in
the substantial absence of moisture. In another preferred
embodiment of the invention, in the ketoximino silanes of the above
formula, R1 has 1 to 5 carbon atoms.
As currently used in sealant compounding, commercial
tetra-functional oximino silanes are either mixed (dissolved) in
trifunctional oximino silanes as described in U.S. Pat. No.
4,503,210 or dissolved in organic solvents.
In the former case solubility limits the level of tetrafunctional
oximino silane in the trifunctional oximino silane to 35-40% at
room temperature. This is disadvantageous because higher levels of
tetrafunctional oximino silane increase cure rate and minimize (if
not eliminate) the need for a catalyst.
In the latter case, solid tetrafunctional oximino silanes were
mixed with hydrocarbons like toluene, benzene and xylene, organic
ethers like diethylether and dibutylether, ketones and halogenated
solvents to facilitate ease of handling in applications which
require precise amounts of tetrafuctional oximino silane. Because
some of these solvents are flammable and carcinogenic, further
precautions must be taken to ensure the safety of personnel during
processing. In addition, one must ensure that the vapor emissions
from the finished sealant products generated during end use are
safe for people and the environment. These precautions are both
costly and time consuming.
Solubility is also a concern. That is, for example, at room
temperature, tetrafunctional MEKO-based silane is only 50% soluble
in toluene and in methyl ethyl ketoxime, 40% soluble in diethyl
ether and 10% soluble in dibutyl ether. As a result, significant
amounts of solvent may be required in the formulation. In addition,
crystallization can occur at lower temperatures (i.e., e.g., during
shipping in winter months) and at higher concentrations of the
tetrafunctional oximino silane.
Because of this, there has been a long felt need in the industry
for tetrafunctional oximino silanes which do not require organic
solvents or mixing with trifunctional oximino silanes. We have
surprisingly discovered that the novel tetrakis oximino silanes of
our invention, e.g. tetrakis-(methyl isobutyl ketoximino) silane
and tetrakis-(methyl amyl ketoximino) silane are liquids and thus
do not suffer with the same problems as their solid counterparts.
These new silanes offer the ability to employ solvent-free
formulations, if not significantly decrease solvent content in the
composition. In addition, there is added flexibility and
simplification when formulating room temperature moisture-curable
silicone compositions. Because the new silanes are liquid
tetrafuctional oximino silanes, one can add more of these silanes
to increase the cure rate of the composition. The amount of other
tetrafuctional oximino silanes which can be used in this type of
silicone composition is limited by their solubility in the
solvent.
That the novel tetrafunctional oximino silanes are liquid is
surprising since generally, physical states of organic compounds
transform from gas to liquid to solid as molecular weight increases
in a homologous series. See, R. T. Morrison and R. N. Boyd, Organic
Chemistry, 91-4 (5th Ed. 1987). For example, in the aliphatic
hydrocarbon series, lower molecular weight compounds like propane
(MW 44) and butane (MW 58) are gases, higher molecular weight
hydrocarbons like hexane (MW 86) and octane (MW 114) are liquids
and the long chain hydrocarbon paraffin's like eicosane (MW 282.6),
docosane (MW 316.6) and tetracosane (MW 338.7) are solids.
In the instant case, since tetrafunctional oximino silanes of lower
molecular weight alkyl ketoximes like acetone oxime (MW 73 ) and
methyl ethyl ketoxime (MW 87) are solids, we also expected
tetrafunctional oxime silanes of methyl isobutyl ketoxime and
methyl amyl ketoxime which have higher molecular weights ( 115 and
129 respectively) to be solids. However, surprisingly, we
discovered that both the tetrafunctional oximino silanes of the
invention, are liquids at room temperature.
In addition to the novel liquid tetrafunctional oximino silanes, we
have also discovered unexpectedly, that when oximino silanes
(tetra-oximino, tris-oximino or bis-oximino) of the invention are
formulated with hydroxyl terminated polydimethylsiloxane (HTPDMS),
a well known silicone polymer, an optically clear silicone rubber
results. This is surprising because generally when commercially
available oxime silanes have been combined in typical and useful
concentrations with silicone polymers, a very cloudy and opaque
rubber results. (Compare Examples 1-9 with Comparative Examples 1-4
below). This has limited the number of applications in which these
materials can be utilized. In light of our discovery, the door is
now open to a variety of applications in which aesthetics are
important and from which oxime silanes have traditionally been
excluded.
The novel ketoximino silanes of the invention may be prepared by
following the syntheses outlined below. See, U.S. Pat. No.
4,400,527. Alternately, they may be prepared by any means known in
the art. We note that the oximes used in the syntheses below may be
prepared by any means known in the art. See, for example, the
syntheses outlined in U.S. Pat. Nos. 4,163,756 and 3,991,115 both
to Allied Signal Inc.
The novel silanes of this invention can be used in combination with
other crosslinking agents, which include other oximino silanes as
well as alkoxy silanes and alkoxy-oximino silanes. Examples of such
silanes are disclosed in the following publications: U.S. Pat. Nos.
3,697,568; 3,896,079; 4,371,682 and 4,657,967.
Preparation of tetrakis-(methyl isobutyl ketoximino) silane
A 1 liter 3-necked flask equipped with a condenser, thermometer and
dropping funnel was charged with 350 ml of hexane and 96.7 g (0.84
mol) of distilled methyl isobutyl ketoxime. A drierite tube was
attached to the condenser to ensure a dry reaction medium. The
reaction flask was then placed in a cold water bath. While the
hexane/ketoxime solution was stirred using a magnetic stirrer, 17 g
(0.1 mol) tetrachloro silane was added dropwise into the reaction
flask. The reaction temperature was maintained between 35.degree.
and 42.degree. C. during the addition. After the addition of
tetrachloro silane was complete, the reaction mixture was stirred
for 5 minutes and then allowed to settle for 5 minutes. The
colorless hexane solution top phase was separated from the viscous
methyl isobutyl ketoxime hydrochloride bottom phase using a
separatory funnel. The top phase was then treated with anhydrous
ammonia gas from a cylinder for 10 minutes. The solid ammonium
chloride that separated out was filtered off and the colorless
filtrate was subjected to distillation under reduced pressure
(50.degree. C. at 5 mm Hg) on a rotovap to remove hexane. About 42
g (86%) yield) of a colorless liquid was obtained. The identity of
this material as tetrakis-(methyl isobutyl ketoximino) silane was
confirmed by proton and carbon-13 NMR and GC/Mass spectral
data.
Preparation of tetrakis-(methyl amyl ketoximino) silane
A 2 liter three-necked round bottom flask, fitted with an addition
funnel, condenser and thermometer, was charged with 1300 ml of
hexane and 418.6 g (3.24 mol) of methyl amyl ketoxime. While the
solution was being stirred by means of an overhead stirrer, 67.96 g
(0.4 mol) of tetrachloro silane was added dropwise over a period of
30 minutes during which time the reaction temperature was kept
between 37.degree.-42.degree. C. After the tetrachloro silane had
been added, the reaction mixture was allowed to stand for five
minutes. The cloudy top phase was separated from the methyl amyl
ketoxime hydrochloride bottom phase using a separatory funnel.
Then, the top phase was neutralized with anhydrous ammonia over a
period of 15 minutes and the solid ammonium chloride produced was
filtered off. The hexane was removed from the filtrate under vacuum
to give 178.5 g (82.6%) of a liquid. The identify of this liquid
was confirmed as tetrakis-(methyl amyl ketoximino) silane by IR and
proton and carbon-13 NMR spectral data.
PREPARATION OF ALKOXY-OXIMINO SILANES MIXTURE
Reaction of tetrachlorosilane:ethanol:methyl amyl ketoxime at 1:1:7
mole ratio:
A 1 liter 3-necked flask equipped with a condenser, dropping funnel
and reflux condenser fitted with a drying tube was charged with 348
g of hexane, 11.5 g (0.25 mol) of ethanol and 232.2 g (1.80 mol) of
distilled methyl amyl ketoxime. While the alcohol, oxime and hexane
solution was stirred using an overhead mechanical stirrer, 42.5 g
(0.25 mol) of tetrachlorosilane was added dropwise into the
reaction flask. During the addition, the reaction temperature was
maintained between 35.degree. and 42.degree. C. After the addition
of tetrachlorosilane was completed the reaction mixture was stirred
for 5 minutes and then allowed to settle for 5 minutes. The top
phase was separated from the viscous methyl amyl ketoxime
hydrochloride bottom phase using a separatory funnel. The top phase
was neutralized with ammonia gas from a cylinder for 10 minutes.
The precipitated ammonium chloride solid was separated by
filtration. The clear colorless filtrate was stripped of hexane to
give 94.0 g of a colorless liquid. Gas chromatographic analysis of
the liquid showed that it contained triethoxy(methyl amyl
ketoximino) silane (5.6%), diethoxybis(methyl amyl ketoximino)
silane (12.5%), ethoxytris(methyl amyl ketoximino) silane (43.2%),
tetrakis (methyl amyl ketoximino) silane (33.9%) and methyl amyl
ketoxime (4.5%). The identity of these silanes was confirmed by
GC-mass spec analysis.
Preparation of methyl tris-(methyl isobutyl ketoximino) silane
A 5 liter, three-necked and water jacketed flask, fitted with
thermometer, overhead stirrer and addition funnel, was charged with
714.3 g (6.20 mol) of methyl isobutyl ketoxime and 3000 ml of
hexane. One mole or 149.48 g of methyltrichlorosilane was added
dropwise over a period of 1 hour during which the reaction
temperature was maintained between 37.degree.-42.degree. C. After
the addition of methyltrichlorosilane was complete, the reaction
mixture was stirred for 5 minutes and allowed to stand for 10
minutes. The top phase was separated from the methyl isobutyl
ketoxime hydrochloride bottom phase using a separatory funnel and
neutralized with ammonia gas by bubbling the ammonia through the
liquid for 10 minutes. Solid ammonium chloride was filtered off and
hexane was removed from the filtrate by vacuum distillation to give
380 g (98.7%) of a colorless liquid. The identity of the product as
methyl tris-(methyl isobutyl ketoximino) silane was confirmed by IR
and proton and carbon-13 NMR spectral data.
Preparation of vinyl tris-(methyl isobutyl ketoximino) silane
A 3 liter, three-necked, round bottomed flask equipped with an
overhead stirrer, thermometer and addition funnel was charged with
714.0 g (6.20 mol) of methyl isobutyl ketoxime and 1200 ml of
hexane. While stirring, 161.5g (1.0 mol) of vinyltrichlorosilane
was added dropwise over a period of 1 hour and the reaction
temperature was maintained between 37.degree.-41.degree. C. After
the addition was complete, the reaction mixture was allowed to
stand for 10 minutes. The top phase containing product and hexane
was separated from the bottom phase (methyl isobutyl ketoxime
hydrochloride) using a separatory funnel and neutralized with
ammonia gas for 10-15 minutes. Solid ammonium chloride was filtered
off and hexane was removed from the filtrate by distilling under
reduced pressure to give 374 g (94%) of a colorless liquid. The
identity of this liquid as vinyl tris-(methyl isobutyl ketoximino)
silane was confirmed by IR and proton and carbon-13 NMR spectral
data.
Preparation of methyl tris-(methyl amyl ketoximino) silane
A 2 liter, three-necked, round bottomed flask, fitted with a
thermometer, overhead stirrer and addition funnel was charged with
394.1 g. (3.05 mol) of methyl amyl ketoxime and 1000 ml of hexane.
While stirring the contents in the flask, 74.5 g (0.5 mol) of
methyltrichlorosilane was added dropwise from the addition funnel
over a period of 30 minutes. During the addition, the reaction
temperature was maintained at 35.degree.-41.degree. C. After the
addition was complete, the reaction mixture was allowed to stand
for 10 minutes. The top phase containing hexane and the product was
separated from the heavy methyl isobutyl ketoxime hydrochloride
bottom phase using a separatory funnel. The top phase was
neutralized with ammonia gas by bubbling the ammonia through the
liquid for 10 minutes. Solid ammonium chloride was filtered off and
hexane was removed from the filtrate by distillation under reduced
pressure to give 201.8 g (94.5%) of a colorless liquid. This liquid
was identified by IR and proton and carbon 13 NMR spectral data as
methyl tris-(methyl amyl ketoximino) silane.
Preparation of vinyl tris-(methyl amyl ketoximino) silane
A 2 liter, three-necked flask fitted with overhead stirrer,
addition funnel and thermometer was charged with 236.4g (1.83 mol)
of methyl amyl ketoxime and 800 ml of hexane. While the contents of
the flask were stirred, 48.45 g (0.3 mol) of vinyltrichlorosilane
was added dropwise from the addition funnel over a period of 30
minutes during which the reaction temperature was maintained
between 32.degree.-41.degree. C. After the addition of
vinylchlorosilane was complete, the reaction mixture was allowed to
stand for 10 minutes. The top phase containing product and hexane
was separated from the heavy bottom phase (methyl amyl ketoxime
hydrochloride) using a separatory funnel and neutralized with
ammonia gas by bubbling the ammonia through the liquid for 10
minutes. Ammonium chloride was filtered to give a clear filtrate.
Hexane was removed from the filtrate by distilling under reduced
pressure to give 115 g (87%) of a colorless liquid which was
identified as vinyl tris-(methyl amyl ketoximino) silane by IR and
proton and carbon-13 NMR spectral data.
Preparation of methyl vinyl bis-(methyl isobutyl ketoximino)
silane
Into a 500 ml, three-necked flask, fitted with thermometer,
condenser and dropping funnel, was charged a solution of 47.17 g
(0.41 mol) of methyl isobutyl ketoxime and 250 ml of hexane. While
stirring this mixture by means of a magnetic stirrer, 14.11 g (0.1
mol) of methyl vinyl dichlorosilane was added dropwise from the
addition funnel over a period of 15 minutes. The reaction
temperature was maintained between 33.degree.-38.degree. C. After
the addition of chlorosilane was complete, the reaction mixture was
allowed to stand for 5 minutes during which the phases separated.
The top phase was separated from the oxime hydrochloride bottom
phase by means of a separatory funnel. The top phase was
neutralized with ammonia gas by bubbling the ammonia through the
liquid for 10 minutes and the precipitated ammonium chloride was
filtered off. Hexane from the filtrate was removed by distillation
under reduced pressure to give 27.5 g (89%) of a colorless liquid
which was identified as methyl vinyl bis-(methyl isobutyl
ketoximino) silane by IR and proton and carbon-13 NMR spectral
data.
Preparation of methyl vinyl bis-(methyl amyl ketoximino) silane
A 3 liter, three-necked flask fitted with an overhead stirrer,
addition funnel and thermometer was charged with 529 g (4.1 mol) of
methyl amyl ketoxime and 1200 ml of hexane. While stirring the
contents of the flask, 141 g (1.0 mol) of methyl vinyl
dichlorosilane was added dropwise from the additional funnel over a
period of 40 minutes during which the reaction temperature was
maintained between 28.degree.-32.degree. C. After the addition was
complete, the reaction mixture was allowed to stand for 10 minutes
to form two phases. The top phase containing product and hexane was
removed from the oxime hydrochloride heavy phase using a separatory
funnel and neutralized with ammonia gas by bubbling the ammonia
through the liquid for 10 minutes. Ammonium chloride solid was
filtered and hexane was removed from the filtrate by distillation
under reduced pressure to give 286 g (87.7%) of a colorless liquid.
This liquid was identified as methyl vinyl bis-(methyl amyl
ketoximino) silane by IR and proton and carbon-13 NMR spectral
data.
EXAMPLE 1
To a 100 ml beaker was added 50 parts by weight of hydroxyl
terminated polydimethylsiloxane (HTPDMS) having a viscosity of
50,000 cst. Then, 1-4 parts by weight of methyl tris-(methyl
isobutyl ketoximino) silane (prepared in accordance with the
synthesis disclosed herein) was added. The compounds were mixed at
25.degree. C. at 200 rpm using a standard laboratory stirrer for 5
minutes. The resulting product cured to a clear silicone
rubber.
EXAMPLES 2-9
The experiment outlined in Example 1 above, was repeated using the
following silanes:
1.) 1-4 parts by weight methyl tris-(methyl amyl ketoximino)
silane;
2.) 2-3 parts by weight vinyl tris-(methyl amyl ketoximino)
silane;
3.) 2-3 parts by weight vinyl tris-(methyl isobutyl ketoximino)
silane;
4.) 1-3 parts by weight tetrakis-(methyl amyl ketoximino)
silane;
5.) 1-3 parts by weight tetrakis-(methyl isobutyl ketoximino)
silane;
6.) 3:1 parts by weight of a mixture of methyl tris-(methyl
isobutyl ketoximino) silane and tetrakis-(methyl isobutyl
ketoximino) silane;
7.) 3:1 parts by weight of a mixture of methyl tris-(methyl amyl
ketoximino) silane and tetrakis-(methyl amyl ketoximino)
silane;
8.) 3:1 parts by weight of a mixture of methyl tris-(methyl amyl
ketoximino) silane and tetrakis-(methyl isobutyl ketoximino)
silane.
The results were the same as those reported in Example 1. That is,
the resulting cured silicone rubber was clear.
Comparative Example 1
To a 100 ml beaker was added 50 parts by weight of HTPDMS, having a
viscosity of 50,000 est. Then, 3-4 parts by weight of methyl
tris-(methyl ethyl ketoximino) silane was added. The compounds were
mixed at 25.degree. C. and 200 rpm using a standard laboratory
stirrer for 5 minutes. The resulting product cured to an opaque,
cloudy silicone rubber.
Comparative Examples 2-4
The procedure outlined in Comparative Example 1 was repeated using
the following silanes:
1.) 2-10 parts by weight vinyl tris-(methyl ethyl ketoximino)
silane;
2.) 3-10 parts by weight tetrakis-(methyl ethyl ketoximino) silane
in toluene;
3.) 3:1 parts by weight of a mixture of methyl tris-(methyl ethyl
ketoximino) silane and tetrakis-(methyl ethyl ketoximino)
silane.
The results are the same as those reported for Comparative Example
1. That is, the resulting product cured to an opaque, cloudy
silicone rubber.
The silanes of the invention have utility as intermediates in the
preparation of various one-component room-temperature-curing
compositions for sealant, adhesive, coating and other silicone
polymer applications. These one-component systems may be prepared
in accordance with the teachings of U.S. Pat. No. 3,189,576 to
Sweet (Example 17 at col. 12, lines 6-26) and U.S. Pat. No.
4,720,530 to Wurminghause et al. at col. 1, lines 60-67 and col. 2,
lines 1-43 which disclosures are hereby incorporated by reference.
Generally, the method for preparing one-component
room-temperature-curing compositions comprises reacting in the
substantial absence of moisture a hydroxy-endblocked siloxane
polymer with a silane. Optionally, fillers such as silica, chalk
and glass beads, adhesion promoters such as organofunctional
silanes and catalysts such as tin carboxylates, dibutyl tin
diacetate, and dibutyl tin dilaurate, lead carboxylates, zinc
carboxylates and organo titanates may be included in these
formulations.
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